We tend to expect that all causes will have roughly the
same significance. That all customers are equally valuable. That every bit of
business, every product and every dollar of sales revenue is as good as
another. That all employees in a particular category have roughly equivalent
value. That each day or week or year we spend has the same significance.
That all our friends have roughly equal value to us. That all enquiries or
phone calls should be treated in the same way. That one university is as
good as another. That all problems have a large number of causes, so that it
is not worth isolating a few key causes. That all opportunities are of roughly
equal value, so that we treat them all equally.
We tend to assume that 50 per cent of causes or inputs will account
for 50 per cent of results or outputs. In reality it’s more like 80 per cent input accounts for 20 per cent of the outputs.